Cardiovascular rhythms, particularly regular arterial pulsations driven by heartbeat, are associated with efficient glymphatic clearance of β-amyloid (Aβ); atrial fibrillation reduces glymphatic function by 28% and correlates with lower cognitive scores, indicating that disrupted cardiac rhythm impairs brain waste clearance.

The heartbeat creates rhythmic pressure waves that squeeze fluid-filled channels around brain arteries, pushing cleaning fluid into the brain to flush out waste. Astrocytes, a type of brain cell, position special water channels on their ends to guide this fluid flow. When the heartbeat is regular, these channels stay properly aligned and the fluid moves efficiently. When the heartbeat is irregular, the squeezing stops being smooth, the fluid doesn't flow well, and waste builds up.